Imagine the scene. We’re at a meeting of the shadow cabinet and it’s Andy’s turn to offer an idea. He opens his briefcase to discover that he’s left his proposal for the reorganisation of the NHS at home. What does he say? From the other side of the table, Ed Miliband gives him that eerie look of his – as vacuous yet mysterious as a cow staring at the moon.

Come on Andy, think of something! A petting zoo in children’s wards? Free wigs for the under-fives? Inner city sumo? He casts his mind back to the last thing he did (eat breakfast), and blurts out, “Let’s ban Frosties!” There’s a long, awkward silence. “They’re packed with sugar … And, uh, if the parents keep on feeding their kids on them … they’re going to grow up to be the size of … cows?”

Ed's bovine stare turns into a smile. “I like it,” he says. And, lo, another Labour Party policy is born.

Labour is supposed to be burying its Brownite associations with nannying and bureaucracy. So it seems perverse that Burnham should declare war on Tony the Tiger in the name of bringing Britain down to size. True, Britain has a weight problem and it needs to be confronted. But Labour's front bench don’t seem to understand that the public doesn’t like it when politicians – of any party – try to tell us what to do. MPs lack the moral capital. Some of them sent us to war for the wrong reasons, others were caught diddling their expenses to have their duck houses covered in gold leaf. And the waistbands of many suggest that they probably enjoy the odd bowl of Frosties themselves. If you combined the breakfast plates of Ed Balls and Eric Pickles, you could probably feed Africa for a month.

Despite all of this, politicians on Left and Right continue to speak as if their dusty copy of Jane Fonda’s Workout Video qualifies them to tell the rest of us that we need to get in shape. It's a compulsion that's innate to politics – power creates an itch to meddle. We’ve had wars on smoking, alcohol, bad school meals (Earth to Jamie Oliver – all school meals are, by their nature, bad) and now sugar. This restless Puritanism is found on both sides of the chamber. Gambling, for example, can easily become a sickness, and I read with disgust a report by Fairer Gambling that says that betting shops are targeting poor communities. But the responses given by MPs were irritating. Lucy Powell, Labour MP for Manchester Central, said, “I think it is a moral question to ask whether it is a good thing that betting companies are targeting the poor and whether government lets them.” Why shouldn’t the government let them and what can it do to stop them? Ban betting shops in poor areas (discrimination) or limit them to one per high street (creating a monopoly)? And isn’t there a wider moral question of why people gamble?

Alas, when a Tory addresses that question he inevitably comes off like a Dickensian vicar. Step forward John Redwood. He said, “I put [excessive gambling] down to the fact that poor people believe there's one shot to get rich. They put getting rich down to luck and think they can take a gamble. They also have time on their hands. My voters are too busy working hard to make a reasonable income.” So John Redwood’s advice on how to quit gambling is to get a job in finance and move to Wokingham? It seems on matters moral that the public faces an unpleasant choice between the authoritarianism of Labour and the snobbery of the Tories. Doubtless, Labour wouldn’t allow “monkey tennis” for reasons of animal rights – but the Conservatives wouldn’t allow it for fear that it might lower the tone of the area.

Regardless of the rights and wrongs of one moral crusade or another, the politicians are up against a sad truth of human nature: whatever we’re told not to do … that’s the thing that we want to do the most. Tell me not to smoke, and I’ll blow all my money on Marlboros. Tell me to drink less, and mine’s a pint. In fact, now that I know I’m not supposed to eat Frosties either, breakfast will become Frosties doused in vodka, finished off with a deep-fried Mars Bar and washed down with supermarket vodka – and I might bet the house on a horse while I do it. Because something never seems more necessary nor pleasurable than when political consensus tells me it's wrong.

Sorry Andy, but you’ll have to take my Frosties from my cold dead hands.